Theorization in progress; Mindblowing Minisculities and Goosebump PR-Bandpass...

[Wolf]

I've been meaning to build the PR-Bandpass version of Goosebump (originally designed as a vented bandpass), and have now modeled and setup the best mockup I can prior beginning the build. The PR is *JUST* big enough to allow the TB W3 to pass through. I might even have to truncate the active driver's frame a smidge. Just so happens that a prefab box from another vendor will actually fit the need quite readily. I would not call it a subwoofer, no, but it will augment a 2" driver satellite that can't do what it can. The woofer is the TB W3-1876S paired with the Peerless 830878 3.5" PR. I will use the 320-608 2.1 channel amplifier as the integration unit. I'm still going through the application of the woofer module to make sure everything will indeed fit. This is not something with a lot of real estate. A veritable shoehorn will indeed ensue.



The culminating criteria that resulted in the Mindblowing Minisculities are due to: having drivers the same size as these acquired cubes' faces, knowing that BSC is not required in omni designs, having drivers with fairly low sensitivity, wanting to do an omni design, and the experience of seeing/hearing Dan's 'Waveguide Omnis' at InDIYana 2021 a few weeks ago. These are higher-Qts poly coned drivers that PE is selling currently through Ebay and their site, but quantities are limited and then they'll be an MOQ item. Dan's design used waveguides' rear-sides in a process similar to how Duevel designs their offerings with up-firing mid and woofers. The departure of the design and revelation was that he stuffed their front-sides and left their entrances open in front of the drivers. This cut down the individual drivers' breakups, and made them easier to manage. Since 2" curvilinear conical waveguides are scarce, and that convex waveguides have also been used in such designs as these, and that I happened to have 1.75" whiffle balls at the ready doing nothing; I used the hot knife to sever it into 2 equal halves, and stuffed them like Dan did.

The 2.25" cubes were $1 each at a buck-store, and with a 2" Forstner bit and a touch of sanding involved, the drivers drop right in. I stained/finished with polyshades black, including the 11/16" long spools used as standoffs. 4 screws, 5g of polyfill, and a 125uF capacitor, and an Ultratouch stuffed half of a 1.75" whiffle ball later; and this was connected and running! It literally took me an afternoon to get these together.



I hooked the MM up to the Lepai 2020Ti, and was actually VERY impressed! Vocal range was really clean and clear, even if the treble wasn't sparkly or the bass very deep. Then I took the measurements, and it really wasn't awful! There is definitely nothing to make these fatiguing, and as-is they aren't awful sounding to start with.



And a simple notch later:



More to come...
Wolf

[Wolf]

I need to paint the tops of the MM yet, and then they'll look better.

Bandpass Xmax plot, nets 92dB:



The inside of the MM is pretty benign and boring:



More on the woofer module to come as it gets built...
Wolf

[Unbiasedsound]

Those speakers remind me of the Mirage Omni sat speakers that I use to own awhile back as they had a really spacious sound and very smooth sounding. They were 2 way with some type of wave guide over the small woofer and a wave guide on the tweeter. The wave guides were angled so I dont think they were true (360) omni directional.

[Chris Roemer]

ALWAYS an entertaining read, Ben.

[djg]

Finally, the Bose Buster is manifested in reality.

That W2-1803SM not coming up as a model #. For me anyway.

[a4eaudio]

That W2-1803SM not coming up as a model #. For me anyway.

I see an -1803S and an -803SM but can't tell from the pic in post #1 which it is.

[Wolf]

Went from memory, definitely w2-1803, whatever the extension. Black poly cone, no phase plug.
Wolf

[ugly woofer]

W2-1803sm

[djg]

Minimum order item when they run out.

https://www.parts-express.com/Tang-Band-W2-1803S-2-Neodymium-Poly-Full-Range-Driver-264-885

[Paul Carmody]

Looks awesome. What was the original purpose of these cubes?

[djg]

https://www.dollartree.com/craftwood-cubes-225-in/313460

[joeybutts]

This is an awesomely intriguing design. Love this kind of stuff. Nice wolf.

[Wolf]

Wow, dig, you are on it with the related links! Thank you!

Amazing how cheap the cabs are, and how little coin I actually have in these, and how decent they sound without a filter.
I was given the 2" drivers some time ago.
The cubes and whiffle ball I had at the ready. Things my wife had for whatever the reason. I use the spools for standoffs, so I had them.
The acrylic was a scrap piece I cut down.
Who doesn't have screws and glue?

FWIW, the other 2" TB drivers are the same frame size, and will apply, though with a different filter.
Later,
Wolf

[djg]

I was putting a cart together for this, but it started getting a bit pricey. I think I'll sit this one out. I don't have any of this stuff sitting around.

Edit: I did order a pair of the TBs.

[Wolf]

Looks like a trip to DT is in order...

[joeybutts]

Looking to be about $120 and some scraps to get these done for a nice, background hidden ambience system.

I am highly considering this for my kitchen and alexa'ing/heos this little system to the living room. Easy to hide up on the kitchen cabinets or even behind the mixer and coffee maker.....so cool going with the Omni setup....

[Wolf]

Just pick the 2.1 amp you want to use, and done!

The model for the woofer does not have added mass on the PR, just for info's sake. Use your judgement on the highpass cap for it if you plan on banging on it pretty hard. Anywhere from 500-800uF is probably a good spot. Light duty = no cap, and semi-light = 1000uF. This is all conjecture, and I plan on testing it out.

Later,
Wolf

EDIT: I might even go Grey-Goose', and run an opposed pair wired in series for vibration cancellation. It would make a good spot to house the amp and such in between.

[tomzarbo]

I like that you're doing this. This is FUN! Not everything has to hit 98 decibels and shake your liver to a froth.
TomZ

[Wolf]

This woofer has come a LONG WAY from the ol' Bass Toaster, hasn't it, Tommy?

[Wolf]

Gotta have a FUN and not so serious build now and then- even if the result is pretty darn good. :-)

I was initially thinking about this getup for a laptop, and the sub would go behind the monitor. I even measured average of vertical off-axis to see what would change. Turns out, not much changed!

Have fun with it!!!
Wolf